Direct sound printing (DSP) employs sonochemistry to derive polymerization in a printing resin medium. The application of ultrasound radiation (20 kHz–10 MHz) to the medium causes the formation of cavitation bubbles. During periods of high pressure, the collapse of these bubbles generates localized hot spots — with temperature values up to 10,000 K — able to initiate chemical reactions within the medium. This ultrasound-driven printing technique enables printing materials such as heat-curing thermosets (that are challenging to process by conventional methods) and remote distance printing (opening to printing beyond physical barriers). However, traditionally, it is confined to a single acoustic focal region, which results in a voxel-by-voxel printing approach. Now, writing in Nature Communications, Muthukumaran Packirisamy and colleagues present a method that enables the distribution of polymerization over entire pressure patterns rather than focusing on one point, enhancing efficiency and expanding the possibilities of the DSP technology.At present, the main drawback is the lack of uniformity of the pressure patterns, which negatively influenced the accuracy of the printed parts. When the pressure values of the image pixels were not uniform, waviness and thickness deviations in the printed pattern were registered (with different levels of polymerization and polymer deposition distributed according to the different pressure levels). To address these challenges, the authors plan to implement computational techniques that can dynamically adjust and optimize pressure distributions during the printing process. Once the quality and consistency of the printed objects are optimized, the prospect of creating intricate multi-material objects and complex tissue structures for biomedical applications, such as skin grafts or organ-repair scaffolds, is envisioned.
